This application is a 371 of PCT/EP01/06859 filed Jun. 19, 2001.
This invention relates generally to perfumes and, more particularly, to a new process for the production of fatty aldehydes.
Lower aldehydes such as 1-octanal or 1-decanal, for example, are sought-after raw materials for the perfume industry. Their production from fatty alcohols, for example by oxidation with hypochlorite in the presence of 4-methoxy-2,2,6,6-tetramethyl piperidin-1-yloxyl (“Tempo”), is known from the prior art. The oxidation of the alcohols with air can be carried out in the presence of ruthenium or platinum catalysts. In addition, unsaturated alcohols can be isomerized to aldehydes under the influence of iron pentacarbonyl. The aldehydes are obtained from fatty acids by hydrogenation on oxidic copper catalysts of the Adkins type or by reaction with per acids in the presence of titanium (IV) oxide. RO 0111820 (Comb. Chim. Rimnicu Vilcea) reports on the use of heterogeneous oxidic copper catalysts for the dehydrogenation of fatty alcohols. Iron-doped copper catalysts are proposed for the same purpose in EP 0320074 A1 (Engelhard). A classic method is the Rosenmund reaction in which acid chlorides are hydrogenated to the corresponding aldehydes on Lindlar catalysts. Reference is made in this connection to the overwiew articles in J. Am. Chem. Soc. 109, 3786 (1987), J. Org. Chem. 52, 2259 (1987) and Tetrahedron Lett. 28, 4575 (1987).
Unfortunately, the known processes have the disadvantage that they are equipment-intensive, give low yields and/or are characterized by unsatisfactory selectivities. Accordingly, the problem addressed by the present invention was to provide a new process which would reliably avoid the above-mentioned disadvantages of the prior art.